Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/06—Contaminated groundwater or leachate

Definitions

• the present invention relates to a new method for purifying groundwater and waste water, and an apparatus for performing the method.
• activated carbon to remove traces of water-polluting substances, in particular organic substances.
• adsorption on activated carbon is uneconomical in order to separate larger quantities of pollutants, which is why water containing large quantities of biodegradable organics is first subjected to a biological cleaning stage. The refractory substances remaining after the biological purification stage are then removed to the trace area by adsorption on activated carbon.
• groundwater and waste water of various origins should be able to be cleaned by the above sequence of biological cleaning stage and adsorption on activated carbon.
• the term groundwater and waste water includes z. B. groundwater, surface water, landfill leachate, domestic waste water, concentrated waste water, process waste water, industrial waste water and mixtures of these waters
• Sand filtration is no longer useful, however, if the degree of soiling fluctuates greatly Water, or strongly fluctuating composition of the pollutants in the water, or also with increased and fluctuating salt concentrations (15-100 g / l) in the water. Then flocculation of the solids after the biological purification stage is difficult or even not possible at all using flocculants.
• the object of the present invention was to provide a method which can overcome the disadvantages of sand filtration, which is suitable for the wide range of contaminated waters mentioned, which can be used on an industrial scale and which improves the cleaning performance of the activated carbon adsorption.
• the tasks outlined above can be solved and, in addition, the degradation performance of the biological stage can be increased in certain cases by a process for the purification of groundwater and waste water, which is characterized in that the water between a biological purification stage and the transfer via activated carbon to a membrane Separation process.
• all biological cleaning and degradation processes can be used for the biological cleaning stage.
• the processes can be carried out aerobically or anaerobically. They are preferably so-called carrier biologies, i.e. the biomass is in a fluidized or fixed bed reactor on a carrier material with a large surface area e.g. Plastic bodies fixed.
• a membrane separation process is understood to mean a separation operation, for example reverse osmosis, ultrafiltration and / or microfiltration, in which a membrane (flat or tubular membrane) is used whose pore size is between 0.001 ⁇ m and 10 ⁇ m, preferably between 0.02 ⁇ m and 10 ⁇ m and particularly preferably between 0.2 ⁇ m and 0.5 ⁇ m.
• a membrane flat or tubular membrane
• a dynamic filtration two different procedures are possible here, firstly a static filtration and secondly a dynamic filtration, which is preferred.
• Static filtrations are also known as "dead end" filtrations and are particularly suitable for removing small amounts of solids.
• Dynamic filtration can continuously remove large quantities of solids; they are removed in the so-called concentrate. Dynamic filtration is carried out, for example, as tangential cross-flow filtration at overflow speeds of 0.5-8 m / s and at system pressures of 2-10 bar. The solids can be separated off to the extent that the concentrate is still free-flowing. The concentrate can then be added to the raw water supply (recycling). In order to maintain sufficient filtration performance, it is generally necessary to carry out periodic backwashing.
• microorganisms can be returned to the biological stage after the separation on the membrane, since the concentrate of the membrane separation process can be added to the raw water supply.
• the concentrate of the membrane separation process can be added to the raw water supply.
• poorly fixed or specialized microorganisms are not lost for the biological stage, but can be recycled. This may result in better biodegradation performance.
• the device for performing the above method consists of a combination of a biological purification stage (bioreactor), a unit for the membrane separation process and an activated carbon adsorption (activated carbon filter).
• bioreactor biological purification stage
• activated carbon adsorption activated carbon filter
• the industrial wastewater to be treated has a TOC (total organic carbon) content of approx. 2000 mg / l and a salt content of 20'000-40'000 mg / l, in addition it contains a few mg / l bioactive, non-degradable Substances.
• TOC total organic carbon
• the biological cleaning takes place in a column (0.5 m in diameter, 4 m in height), which is 80% by volume filled with a plastic packing (approx. 200 m2 / m3 surface).
• the microorganisms for inoculation come from bio-sludge from similar reactors. Air is blown in at the bottom of the reactor for better degradation. The degradation rate is over 95%.
• the biomass resulting from the degradation (mainly bacteria) partly sticks to the surface of the packing, partly it is continuously flushed out of the reactor as fine sludge.
• the total amount of undissolved substances at the outlet of the bioreactor is 500-2000 mg / l (determined according to Swiss standard methods for water analysis).
• the biological cleaning process is conducted at a pressure of approx. 3 bar through a cross-flow microfiltration unit equipped with an inorganic membrane (nominal pore size 0.2 ⁇ m). Approx. 90% of the water passes through the membrane, the rest is retained as a concentrate and returned to the raw water supply. In order to maintain the filtration capacity of approx. 60 l / m2h, a short back pressure surge is applied at intervals of approx. 10-30 minutes, which briefly reverses the flow direction through the membrane without interrupting the overall process. The membrane can be cleaned with Javell lye every few weeks.
• the water that has passed through the membrane has 0 mg / l undissolved substances and is sterile, which means that in the subsequent step the activated carbon is inoculated with microorganisms.
• the final cleaning step is activated carbon adsorption in a fixed bed adsorber, contact time about 1 hour.
• the TOC content of the wastewater purified in this way is 20-100 mg / l; bioactive, non-degradable substances can no longer be detected.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Biological Treatment Of Waste Water (AREA)
• Water Treatment By Sorption (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 1991
  • 1991-07-30 EP EP19910810605 patent/EP0470931A3/de not_active Withdrawn
  • 1991-08-05 US US07/739,964 patent/US5230803A/en not_active Expired - Fee Related
  • 1991-08-07 ZA ZA916219A patent/ZA916219B/xx unknown
  • 1991-08-07 AU AU81702/91A patent/AU8170291A/en not_active Abandoned
  • 1991-08-08 JP JP3198154A patent/JPH04227099A/ja not_active Withdrawn

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